BALTIMORE — Michael Phelps entered the 100-meter butterfly final at the 2009 world championships in Rome in no real shape to contend. Less than an hour before the race, Phelps had collided head-first with another swimmer during a warmup, leaving him with blurred vision in one eye and cracked goggles. He had not trained full-bore since winning eight gold medals at the 2008 Olympics, and the night before, Serbian rival Milorad Cavic had broken his world record.

On top of all that, Phelps wore an older, slower model speedsuit than Cavic in the last major meet in which they were legal.

Phelps’s longtime coach, Bob Bowman, was so pessimistic about Phelps’s chances, he considered not watching the final. But in the days before the race, Cavic made a mistake for which he would pay dearly: He taunted Phelps, saying he would buy him a faster speedsuit if he couldn’t get a company to offer one for free.

In the first 50 meters, Cavic took a commanding lead and remained in front entering the final meters of the race. That’s when Phelps closed fast, blowing past Cavic to win the gold and reclaim his world record.

“Michael’s brain chemistry is such that he almost has to have that competitive environment,” Bowman said. “When he has it in his brain, it’s like unshakeable. . . . Part of it is a supreme confidence. Part of it is, he thinks he’s better than everyone else. And he is.”

There is no doubt Phelps is one of the most physically gifted athletes in history. But his performance in Rome, the eight gold medals he claimed in eight races under immense pressure in Beijing, and various other successes throughout his professional career suggest that his most valuable attribute is actually his mind. Bowman called Phelps the strongest-willed, most unflappable competitor he’s observed in any walk of life.

“He just has this confidence in his ability to get the job done whether he’s prepared for it or not,” Bowman said.

For most athletes in Olympic sports, any hope of meaningful success, financial rewards and public accolades will come down to an ability to perform in a narrow competitive window, sometimes as small as a minute or two. Because of the inherent high pressure and enormous stakes, athletes who demonstrate mental weakness will not win medals at this summer’s Olympics in London regardless of their talent or physical skills, U.S. Olympic Committee Sport Psychologist Sean McCann said.

“The pressure at the Olympic Games is really, really, really overwhelming, even if you are incredibly experienced,” said Natalie Coughlin, a two-time Olympian who has won 11 Olympic medals. “The feeling of walking onto the pool deck, standing behind the blocks knowing the race that you’ve prepared for the last four years, or the past decade, [that] everything is going to culminate in that 58 seconds or so, it’s quite stressful.”

McCann said mental tools to deal with pressure and nervousness can be learned and developed, but mental strength — just like muscular strength or other attributes — is a trait some athletes naturally possess in abundance, and others forever struggle to attain.

Phelps’s mental tenacity appears to be partly innate and partly shaped through years of experience. For sure, however, it is not anything he has pondered deeply, or resolutely practiced.

Phelps has never consulted with a sports psychologist. When Bowman did set Phelps up with a therapist during his first year at the University of Michigan, he forbid the counselor from discussing swimming for fear such talk could only do harm.

“Everybody is put on this earth with certain things they’re good at,” Phelps said. “Certain things they can do. Obviously, I’ve been able to handle pressure pretty well . . .Throughout my career I’ve risen to the occasion when obstacles come my way. That’s something, I guess, I was given.”

‘Simplicity and certainty’

Mental strength can be broken down into two key components, McCann said. The first is an unyielding desire for victory and superiority in competition regardless of the pressure, which is known as an offensive mental aptitude, he said.

This allows an athlete to use the energy surges or adrenaline produced from high-pressure situations to enhance concentration, strength and execution — rather than to produce nervousness, panic, muscle tightening or over-exertion.

The second component, McCann said, is a defensive skill, a resilience that allows an athlete to roll with unforeseen circumstances such as a bad lane assignment, a poor night’s sleep — or a head-to-head collision just before racetime.

Only some athletes, he said, possess one of the two. Very few, he said, display both.

”The easiest thing for me is to predict the ones who will fail,” McCann said. “The ones who are weak mentally never succeed at the Olympic Games because their vulnerabilities are exposed . . . For the absolute best performance, what you need is simplicity and certainty.”

When Phelps arrived in Beijing in 2008, he was nothing short of the centerpiece of those Games. Speedo had offered a $1 million bonus if he could achieve eight gold medals in eight events. NBC had requested that the swimming schedule be turned upside down — finals in the early mornings, Beijing time, instead of evenings as is customary — to accommodate the interest in Phelps’s quest for the U.S. prime-time television audience.

McCann called the expectations Phelps faced to be “so outsized they were almost at an unfair level.”

“That’s part of what’s so unique about that story,” McCann said. “That’s probably one of the most spectacular mental efforts” in sports history.

‘Under stress, you just focus’

Bowman saw a deep drive to win in Phelps even before he coached him, though the trait did not display itself admirably in his pre-teen days. Bowman recalled watching Phelps, who took medication for ADHD throughout elementary school, playing an invented game with a tennis ball — the children named it “wall ball” — outside of the North Baltimore Aquatic Club.

“He was ‘out,’ and I remember him just pitching a fit,” Bowman said. “I remember thinking, ‘Who is this kid, who cares whether he’s kicked out of ‘wall ball’ or not when there’s going to be another game in five minutes?’ ”

Phelps and Bowman agreed that Phelps’s natural competitiveness grew as he gained confidence and refined his skills. When Bowman began coaching Phelps at age 11, Phelps despised his imperious coach’s hard-driving style. But Bowman’s methods worked. Phelps got faster and began to dominate kids even much older.

Bowman forced him to participate in multiple events at weekend meets, wanting him to develop his strokes and learn how to race fatigued.

“It was always important to him to do a really good time,” Bowman said. “By the third day of those meets, he would almost have tears in his eyes he was so tired. . . . But I think that’s where he learned that, under stress, you just focus.”

Bowman also demanded full allegiance to his methods. When he tried to force Phelps to adopt a new kick and Phelps refused, Bowman kicked him out of practice for nearly a week until Phelps agreed to implement the change. Despite countless conflicts, Phelps learned, eventually, that he had to do what Bowman wanted him to do.

By the time Phelps got to Beijing, there was comfort in that. Phelps did not second-guess himself because he was not in charge. Phelps took orders and followed them. He assumed Bowman, as always, had gotten the formula right. All Phelps had to do was dive in the water and go.

“Everything we did, he had planned,” Phelps said. “The maestro somehow got everything set into place, and it was my job to sort of let it happen.”

Eight for eight

Though the Beijing Olympics were the third for Bowman and Phelps, who attended the 2000 Games in Sydney at age 15 and won six gold medals and two bronzes at the 2004 Games in Athens, Bowman found himself wracked with nerves.

“I was just sure we weren’t prepared enough,” Bowman said. Phelps “felt like he was completely prepared. I don’t really see that [the pressure] affected him at all. He was really excited by it.”

As Phelps did in Rome when the 100 fly took on elements of a prize fight, he used perceived taunts in the lead-up to the Games to enhance his focus. Before the Olympics, Don Talbot, an Australian coach, and Australian star Ian Thorpe verbalized their doubts about Phelps’s chances of winning eight gold medals.

“I don’t want to say it’s more ammunition, but it kind of is,” Phelps said. “It’s just one thing I’ve always loved, just proving somebody wrong, making them eat their own words. As a kid, I just wanted to beat everybody. I do want to win all the time, but it’s also proving other people wrong.”

Throughout the Games, Phelps unwound each night by playing endless games of spades with fellow U.S. swimmers Ryan Lochte, Cullen Jones and Ricky Berens at the Olympic Village. Phelps said it was obvious that Bowman was nervous, his mother and sisters were nervous and the world was watching. But none of that, he said, disturbed his personal peace.

“At the end of the day, it’s my choice, my race to step up and do well in, or not do well in,” Phelps said. “That’s the part of it that helps me not be affected by anything around me.”

Nearly every race in which Phelps competed featured high drama. World records came in all eight. After a dominant victory in the 400-meter individual medley, Phelps set the American record in the leadoff leg of the 4x100 freestyle relay, which required a record anchor by Jason Lezak to catch up with French star Alain Bernard.

Phelps set another world record in the 200 freestyle. In the 200 butterfly, he won even though his goggles filled with water halfway through, forcing him to count strokes to reach the walls.

“Everything we had worked on his whole career,” Bowman said, “he did to perfection from the [Olympic] trials to the end of that meet.”

To claim his seventh and eighth gold medals, he came from behind against his rival Cavic in the 100 fly, winning on a final lunge by .01 second, and joined a U.S. team that coasted in the 4x100 medley.

“I was super-laid back,” Phelps said. “I was super-calm. . . . I was obviously ready for something that nobody had ever done before . . . and nobody was going to step in my way, nobody was going to get me off track. I was . . . focused on what I needed to do, and I was going to get the job done.”

‘Champions sort of know’

At last year’s world championships in Shanghai, Phelps lost in his only two head-to-head races to Lochte, who has outperformed Phelps internationally since the 2008 Summer Games.

Phelps has blamed all of his subpar performances since Beijing on his failure to commit to full-time training. Bowman has agreed, and frequently expressed frustration with Phelps’s lackadaisical approach. For all of his intensity at big events, Phelps has struggled to work up enthusiasm for lesser meets even when getting occasionally clobbered.

Though Bowman understands that Phelps, now 26, can not train as hard as he did as a teenager, Phelps’s ambivalence about workouts in recent years, and the resulting defeats, have occasionally infuriated him.

“There would be 10 things to correct, and it wouldn’t be, ‘I’m quitting, I [stink],’’ Bowman said of Phelps’s demeanor. “He was never like that. I was always like, ‘You should quit.’ He always had a perspective on it.”

Lochte’s emergence and victories have set up an intriguing Michael vs. Ryan story line this summer. In recent interviews, Phelps says he respects Lochte greatly, but has responded to questions about him mostly with nonchalance.

“I’m pretty much now playing catch-up over the last three years, because I was the one who didn’t want to get in the water and didn’t want to train,” Phelps said.

“Champions sort of always know how to get back to where they once were.”